I think in epilogue would have been better IF the dna fusion had not had worked on terry but had worked on his younger brother, since his he was about the same age when his father died to when bruce's parents died. So they tried it with terry and the phantasm refused

so in a sense, terry's relationship would stop his younger brother from having that vengeful batman side to him, and also if his brother became the new robin and would ultimately become the heir to the batman throne.

so bruce and terry would still have some relation

it would have also made images like this more touching in retrospect, and seeing mat (who has the superhero alliteration in his name already)

plus is would have been a lil less obvious and would all let us know what happened to matt in the end.